I recently bought a MacBook Pro M1 and a SanDisk external ssd. The ssd was working very well at first. I could erase, reformat etc. . I tried also other formatting types and there were no problems. But I wanted to partition my ssd. First I partitioned into two Mac OS extended parts. Then, I partitioned it into 3 parts (2 of them Mac OS extended, 1 ExFat). This operation failed. Then it began to fail.
I could not erase the disk. It always showed an error. I erased from a Windows PC then initialized on the Mac and tried again. It worked well once but then, there were problems while reading and writing. Now I cannot erase the disk. Also cannot use it. It always shows the errors shown below. Also first aid shows the errors shown. How can I fix these errors?
Thank you very much.
ERRORS: (Sorry, I could not upload the screenshots due to storage limit)
When I try to write, read data or expand zip files inside the ssd, it shows the error: "Error identifying a writable temporary folder. Try moving the archive to another volume"
When I try to move an app to the ssd, it says: "The operation can't be completed because an unexpected error occurred (error code -50)"
When I try to erase the whole disk, it shows: "The volume on disk4 couldn't be unmounted because it is in use by process 0 (kernel). Couldn't unmount disk. (-69888)"
When I try to eject it, a warning shows up saying that it is in use and asks me whether I want to force eject.
When I try first aid on the whole disk, it says: "Problems were found with the partition map which might prevent booting"
When I try first aid on the volume named 'External SSD'' it says: "Volume could not be unmounted"
When I list the disks on terminal, it shows my ssd.